A variety of knee braces are currently available for treating different knee problems. Knee braces may be designed to impart forces on limbs surrounding the knee to relieve compressive forces in a portion of the knee. Additionally, knee braces are often employed to support the knee after a knee injury, such as a sprain, or to assist with rehabilitation of the knee after a traumatic event, such as knee surgery.
The human knee is a joint held together by small, powerful ligaments. The femur (i.e., the thighbone) meets the tibia (i.e., the large shin bone) to form the main knee joint called the femoro-tibial joint. The kneecap (i.e., the patella) joins the femur to form a second joint called the femoro-patellar joint. The patella protects the front of the knee. The knee is surrounded by a joint capsule with collateral ligaments strapping the inside and outside of the joint and cruciate ligaments crossing within the joint. The collateral ligaments run along the sides of the knee and limit the sideways motion of the knee. The anterior cruciate ligament (“ACL”) connects the tibia to the femur at the center of the knee and functions to limit rotation and forward motion of the tibia. The ACL divides the knee into an inner (medial) and an outer (lateral) compartment. The posterior cruciate ligament (“PCL”) is located aft of the ACL and limits backward motion of the tibia. The knee also includes a thickened cartilage pad known as a meniscus attached to the tibia and an articular cartridge attached to the femur. The meniscus and articular cartridge function as smooth bearing surfaces that allow for pain-free relative rotation of the femur and tibia.
Despite the knee being held together by powerful ligaments, the knee is still a relatively weak joint that can be easily damaged. For example, the knee may be damaged by participating in sporting events, overloading due to obesity, aging, or misalignment of the knee. Most knee problems are a result of damage of the cartilage of the knee and strain of the ligaments of the knee.
One important knee problem is unicompartmental osteoarthritis in which either the medial (inward) or the lateral (outward) compartment of the knee joint is deteriorated. In a proper functioning knee, both compartments are loaded generally uniformly. A knee joint that suffers from unicompartmental osteoarthritis is characterized by an uneven distribution of pressure in either the medial or lateral compartment of the knee. Such uneven distribution of pressure can wear away the smooth cartilage lining the inside of the knee, which may, consequently, lead to painful, direct contact between the femur and the tibia.
Unicompartmental osteoarthritis may be treated by using a knee brace that is configured to urge the femur and tibia apart in the affected compartment of the knee to reduce or eliminate the painful bone-to-bone contact between the femur and the tibia. However, many conventional knee braces employ complicated mechanisms for applying a load that urges the femur and tibia apart. Despite the availability of such conventional knee braces to treat unicompartmental osteoarthritis, there is still a need for an improved knee brace to treat unicompartmental arthritis in a knee or other joint.